[FIX][mass_editing] Remove view mode space

This resulted in frontend searching for ` tree` view, which of course does not exist.

mass_editing/models/mass_object.py

@@ -63,7 +63,7 @@ class MassObject(models.Model):
             'src_model': src_obj,
             'view_type': 'form',
             'context': "{'mass_editing_object' : %d}" % (self.id),
-            'view_mode': 'form, tree',
+            'view_mode': 'form,tree',
             'target': 'new',
             'auto_refresh': 1,
         }).id

mass_editing/tests/test_mass_editing.py

@@ -78,6 +78,10 @@ class TestMassEditing(common.TransactionCase):
         result = self.mass_wiz_obj.with_context(ctx).fields_view_get()
         self.assertTrue(result.get('arch'),
                         'Fields view get must return architecture.')
+        fields = result.get("fields")
+        self.assertTrue(fields)
+        for name, values in fields.items():
+            self.assertTrue(isinstance(values["views"], dict))
 
     def test_onchange_model(self):
         """Test whether onchange model_id returns model_id in list"""

mass_editing/wizard/mass_editing_wizard.py

@@ -207,6 +207,9 @@ class MassEditingWizard(models.TransientModel):
                                       field.name + "','=','remove')]}"),
                             'colspan': '4',
                         })
+            # Patch fields with required extra data
+            for field in all_fields.values():
+                field.setdefault("views", {})
             etree.SubElement(xml_form, 'separator', {
                 'string': '',
                 'colspan': '6',